Barbers know best when it comes to hair clippers and trimmers, weather you are just knocking your beard down or going to cut your own hair here is a video that can help you pick a decent pair of clippers.
Being a barber every now and then a client ask me about saving himself with a straight razor although i would recommend it is not for EVERYONE to try doing because it is so easy to cut yourself. Sometimes its best left up to the professionals. If you were looking to pick up one of my razors to shave yourself check out this video by one of my favorite other barbers "The Nomade Barber"
Copy and paste this link. https://www.youtube.com/watch?v=sy_BJ_QtbaM in this youtube video is a quick and fast way to adjust the tension of your new hair cutting shears this works for all kinds of shears high quality and low quality of any size and is very simple and easy to understand. Make sure your shears are oiled and tightened properly for the best results cutting.